I have suffered from pains in my knees for many years. The pain comes mainly after exercising but also when my leg has been in an awkward position for too long. It feels fine when I'm walking (except for long periods of time) however, If I go up stairs or get up from a chair I experience a sharp pain in my knees.

I went to the doctor about this problem and they did a complete blood test which revealed I was "dangerously low" in Iron, vitamin b12 and calcium and borderline deficient in folic acid. My thyroid levels were also slightly low. I was referred to a rheumatologist because my doctor said there was definite wear and tear on my joints (they creak and you can feel them grinding when I bend them). However the specialist said that my doctor had lied about this. I got x rays done and a bone scan, and all results were normal. However I'm still experiencing this pain in my knees after exercising. Could it be my poor nutrition that is causing this problem? Or do I most likely just suffer from weak knees?

I'm trying to get my vitamin levels back to normal and I'm taking glucosamine tablets because I've heard that they help bones. But I really need this problem to get sorted out ASAP as it is interfering with my fitness and I have to wear a tight sports knee brace all day long and it is quite hot and uncomfortable.

Thank you for any advice.